JP2005264992A - Electromagnetic shock absorber - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electromagnetic shock absorber that can be applied to a restrictive part in an installing space and ensure a necessary stroke. <P>SOLUTION: The electromagnetic shock absorber comprises a screw shaft 3 rotatably screwed in a screw nut 4 rotatably coupled to a supporting member 23, and a motor 1. The motor 1 is composed of one of a magnet 9 and a coil 8 coupled to the screw nut 4, and the other of the magnet 9 and the coil 8 fixed to the supporting member 23. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention has a mechanism for converting a linear motion of a screw shaft into a rotational motion of a motor via the screw nut by screwing a screw shaft into the screw nut so as to be rotatable, and using the electromagnetic force of the motor as a damping force. The present invention relates to an electromagnetic shock absorber to be used.

  In general, a suspension is known in which a hydraulic shock absorber is interposed between a vehicle body and an axle in parallel with a suspension spring. This suspension suspends the vehicle body and attenuates input such as vibration from a road surface. The ride comfort and controllability are improved, or the vehicle height is kept constant by suppressing the displacement of the vehicle body. This hydraulic shock absorber is advantageous in that a high damping force can be obtained, but on the other hand, oil is required, and a seal mechanism and a complicated valve mechanism for preventing leakage of the oil are required.

  Therefore, recently, a new electromagnetic shock absorber that does not require oil, air, power supply, etc. has been studied and proposed (see Patent Document 1 and Non-Patent Document 1).

The basic structure of this electromagnetic shock absorber is composed of a screw shaft that is rotatably engaged with a ball screw nut, and a motor that is connected to one end of the screw shaft and short-circuits an electrode, and the ball screw nut is a shaft with respect to the screw shaft. The shaft of the motor and the shaft of the motor rotate, and the induced electromotive force generated by the rotation of the shaft attenuates the torque opposite to the rotational direction of the shaft and screw shaft to suppress the linear motion of the ball screw nut. It is used as power.
JP 2003-227543 A (paragraph number 0023, FIG. 1) Suematsu, Suda, "Study on Electromagnetic Suspension in Automobile", Japan Society for Automotive Engineers, Preprint of Academic Lecture, 2000, No4-00

  However, an electromagnetic shock absorber that employs a configuration that transmits the rotational motion of the screw shaft to the motor by connecting the above-described conventional screw shaft and the motor shaft, particularly when applied to a vehicle, Is distributed between the vehicle and the axle, and has the following problems.

  That is, since the electromagnetic shock absorber uses a motor that is not provided in a hydraulic shock absorber or the like, when this motor is connected in series with the screw shaft, the basic length of the whole electromagnetic shock absorber becomes long.

  Therefore, when the electromagnetic shock absorber is disposed between the vehicle body and the axle, the space between the vehicle body and the axle is limited depending on the vehicle type, and the electromagnetic shock absorber is inevitably applied to the vehicle. Since it is necessary to shorten the main body length by the length of the motor, there is a risk of causing a problem that the stroke required for the applicable vehicle cannot be secured.

  Therefore, in order to secure the stroke, the motor may be downsized. In this case, however, the torque output caused by the electromagnetic force generated by forcibly rotating the motor is reduced, and the desired value is obtained. There is a risk that the damping force will not be obtained.

  Therefore, the present invention has been created in consideration of the above-mentioned problems, and the object of the present invention is to apply to an electromagnetic field that can be applied to a part with a limited installation space and can secure a necessary stroke. Is to provide a shock absorber.

  In order to achieve the above-described object, the electromagnetic shock absorber according to the first problem solving means includes a screw shaft that is rotatably screwed into a screw nut that is rotatably connected to a support member, and a motor. In the electromagnetic shock absorber that suppresses axial relative movement between the nut and the screw shaft, the motor is configured by one of a magnet or a coil connected to the screw nut and the other of the magnet or the coil fixed to the support member, An electromagnetic force is generated in the motor, and the electromagnetic force is used as a damping force for suppressing the linear motion in the axial direction of the screw shaft by suppressing the rotation of the screw nut.

  Further, the electromagnetic shock absorber in the second problem solving means is the first problem solving means in which the support member is a cylinder and the screw nut is rotatably fitted in the cylinder and connected to the screw nut. One of the magnet or the coil is made to face the other of the magnet or the coil provided on the inner periphery of the cylinder.

  The electromagnetic shock absorber according to the third problem solving means is characterized in that, in the second problem solving means, the outer peripheral shape of the cylindrical body is a shape with an increased outer peripheral surface area.

  The electromagnetic shock absorber in the fourth problem solving means is characterized in that in the third problem solving means, irregularities or fins are formed on the outer periphery of the cylindrical body.

  Furthermore, the electromagnetic shock absorber in the fifth problem solving means is provided with an outer cylinder connected to one end of the screw shaft and covering the screw shaft in the second problem solving means, and a bearing is provided between the outer cylinder and the cylindrical body. Is provided.

  Still further, the electromagnetic shock absorber in the sixth problem solving means is the fifth problem solving means, in which the cylinder is connected to the vehicle body side of the vehicle, the outer cylinder is connected to the axle side of the vehicle, A suspension spring receiver is provided on the outer peripheral side of the outer cylinder, and a suspension spring is interposed between the suspension spring receivers.

  In the electromagnetic shock absorber according to the seventh problem solving means, in the fifth or sixth problem solving means, a mount for attaching the cylinder to the vehicle body of the vehicle is provided at the end of the cylinder, and the upper suspension spring receiver and A bump rubber is provided, and a bump rubber receiver is provided on the outer cylinder side.

  According to the invention of each claim, since it is not necessary to provide a motor perpendicularly to the upper part of the screw shaft as in the conventional electromagnetic shock absorber, a necessary stroke can be secured for the shock absorber and the basic length can be shortened. . That is, space saving can be achieved. Therefore, it can be applied to parts where the installation space is limited, and the necessary stroke can be secured. Especially when an electromagnetic shock absorber is applied to a vehicle, the basic length can be shortened, which is necessary for the vehicle. Since the stroke of the shock absorber can be secured, the mountability to the vehicle is improved.

  According to the invention of claim 2, since the motor is formed in the cylinder, the magnet and the coil can be formed over substantially the entire length of the cylinder, which was a dead space in the prior art. Without increasing the size, only the motor can be increased in size. That is, since the motor output can be increased without increasing the size of the electromagnetic shock absorber, it is possible to generate a high damping force in the electromagnetic shock absorber.

  Furthermore, since the motor is housed in the cylinder and the cylinder functions as a frame of the motor, the electromagnetic shock absorber can be formed slim and space-saving, so the mountability of the electromagnetic shock absorber is improved.

  In addition, the motor does not have to be attached to the electromagnetic shock absorber as an independent component, and the motor and the electromagnetic shock absorber are integrated. Therefore, durability against the impact from the road surface or the like is superior to that of the conventional electromagnetic shock absorber.

  Furthermore, compared to the case where the motor is an independent part, parts such as a bracket, bolts and nuts for attaching the motor to the electromagnetic shock absorber main body are not required, so the number of parts can be reduced.

  Therefore, assembly and processing become easy, and productivity can be improved.

  Furthermore, the number of parts is reduced, the number of processing steps can be reduced, and the productivity is improved, so that the production cost can be kept low.

  According to the third and fourth aspects of the present invention, the temperature of the motor itself increases due to the heat generated by the coil. However, since the outer peripheral surface area of the cylinder is increased, heat is effectively radiated, so that heat is generated in the cylinder. It can be prevented from being trapped.

  Furthermore, when the electromagnetic shock absorber is applied to a vehicle, the cylinder is sufficiently longer than the motor, and because the electromagnetic shock absorber is attached between the axle and the vehicle body, the cylinder is The wind hits and can effectively dissipate heat.

  In addition, since the temperature rise of the motor can be suppressed, the adverse effect of exceeding the temperature rating of the motor, for example, the insulation deteriorates due to the chemical change of the insulating film of the conductive wire forming the motor coil by the heat generated by the motor itself, As a result, it is possible to prevent a situation where electric leakage or the like occurs and the motor itself is damaged.

  Further, since the motor 1 does not have an individual frame, the heat generated by the motor can be prevented from being trapped in the motor.

 According to the invention of claim 5, the cylinder and the outer cylinder prevent stepping stones from the road surface, rain water, etc. from directly hitting the screw nut, motor and screw shaft, and in addition, the cylinder and the outer cylinder. Since the bearing is provided between the cylinder nut and the screw nut, the shaft of the screw shaft is prevented from being shaken, and it is possible to prevent a load from being concentrated on a part of the ball of the screw nut. Or it is possible to avoid the situation where the screw groove of a screw shaft is damaged. Further, since the screw nut or the screw groove of the screw shaft can be prevented from being damaged, the smoothness of each operation of the rotation of the screw shaft and the screw nut or the movement of the electromagnetic shock absorber in the expansion / contraction direction can be maintained. Since the smoothness can be maintained, the function as an electromagnetic shock absorber is not impaired, and the failure of the electromagnetic shock absorber can be prevented.

 In addition, by providing a bearing between the outer cylinder and the cylinder, it is possible to prevent a situation in which the inner cylinder is displaced relative to the outer cylinder and the inner circumference of the upper end portion of the outer cylinder gnaws the outer circumference of the cylinder. Thus, deterioration of the sealing performance between the outer cylinder and the cylinder is also prevented.

  According to the sixth aspect of the invention, since the cylinder is attached to the vehicle body side, the motor is arranged on a so-called spring. That is, when the electromagnetic shock absorber is applied particularly to a vehicle, by placing the motor on a spring, it is possible to avoid a large load being directly input to the motor from the road surface, thereby reducing the chance of damage to the motor. It becomes possible. Also, by arranging the motor on the vehicle body side, it becomes easy to connect the motor wires to the external control device and control circuit, and the wires are stored in the vehicle body. Damage opportunities can also be reduced.

  According to the invention of claim 7, since the upper suspension spring receiver and the bump rubber are provided on the mount, and the bump rubber receiver is provided on the outer cylinder side, the shock load when the electromagnetic shock absorber fully bounces is applied to the vehicle body. Since it is transmitted, it is possible to prevent damage to the motor.

  The present invention will be described below based on the embodiments shown in the drawings. FIG. 1 is a longitudinal sectional view of an electromagnetic shock absorber according to a first embodiment of the present invention. FIG. 2 is a longitudinal sectional view of an electromagnetic shock absorber according to the second embodiment of the present invention.

  As shown in FIG. 1, the electromagnetic shock absorber according to the first embodiment includes a motor 1, a screw shaft 3, a cylindrical body 23 that is a support member, and a ball screw nut 4 that is a screw nut. 3 is screwed into the ball screw nut 4 to convert the linear motion of the screw shaft 3 into the rotational motion of the ball screw nut 4 to generate an electromagnetic force in the motor 1, and the ball screw nut generated due to this electromagnetic force. 4 is used as a damping force that suppresses the linear motion of the screw shaft 3, and relative movement in the axial direction between the ball screw nut 4 and the screw shaft 3 can be suppressed.

  More specifically, the screw shaft 3 is screwed into a bracket B whose lower end in FIG. 1 is connected to the axle side of the vehicle, and the lower end of the outer cylinder 20 is fitted to the outer periphery of the bracket B. Therefore, the screw shaft 3 is inserted into the outer cylinder 20 via the bracket B and coupled. A cylindrical body 23 as a support member is slidably inserted into the outer cylinder 20 via bearings 21 and 22. A ball screw nut 4 is provided on the inner peripheral side of the lower end portion in FIG. The ball screw nut 4 is rotatably coupled via a ball bearing 5, and a stopper 6 for preventing the ball screw nut 4 from falling off the cylindrical body 23 is screwed to the lower pipe end in FIG. 1. An annular bump rubber receiver 38 is fitted to the upper end of the outer cylinder 20 in FIG. 1, and the space between the cylindrical body 23 and the outer cylinder 20 is sealed on the inner peripheral side of the bump rubber receiver 38. A seal member S is provided.

  Further, a core 7 and a coil 8 wound around the core 7 are fitted on the inner periphery of the cylindrical body 23, and a plurality of magnets 9, 9 rising from the upper end in FIG. 1 of the ball screw nut 4 are connected to the coil 8 and the core 7. It is provided so as to oppose. That is, when the ball screw nut 4 exhibits a rotational movement with respect to the cylindrical body 23, the magnets 9 and 9 rising from the upper end in FIG. 1 of the ball screw nut 4 also rotate, so that the coil 8 is generated by the magnets 9 and 9. An induced electromotive force is generated by crossing the magnetic field.

  Therefore, the motor 1 is a brushless motor including the ball screw nut 4, the cylinder 23, the core 7, the coil 8, and the magnets 9 and 9. In this case, the ball screw nut 4 serves as a shaft and the cylinder. 23 plays a role as a frame. When the outer cylinder 20 is omitted, the ball screw nut 4 can be rotatably supported, and if the motor can be formed, the support member need not be formed in a cylindrical shape. Further, if the ball screw nut 4 can be rotatably supported and a motor can be formed, the support member may be formed on the side where the electromagnetic shock absorber is applied.

  Furthermore, the upper end of the cylindrical body 23 is sealed with a cap 30, and the electric wire 10 connected to the coil 8 of the motor 1 is led to the outside through the cap. The electric wire 10 of the motor 1 is connected to a control circuit or the like (not shown), or is short-circuited so as to directly connect the electrodes (not shown) of the motor 1 to form a closed circuit. By generating a torque that resists the rotation of the ball screw nut 4 caused by the above, adjustment is made to obtain a desired damping force. When this electromagnetic shock absorber is used as an active suspension, it is possible to drive the motor 1 by actively energizing the motor 1 so that it functions not only as a shock absorber but also as an actuator. Further, a ball bearing 35 is fitted to the lower outer periphery in FIG. 1 of the cap 30, and the outer periphery of the ball bearing 35 is fitted to the inner peripheral side of the magnets 9, 9 of the motor 1. , 9 is prevented, and the magnets 9, 9 are prevented from interfering with the screw shaft 3 and the coil 8. Instead of the ball bearing 35, a bearing slidably contacting the inner periphery of the magnets 9, 9 may be provided.

  In the case of a brushless motor, a Hall element, a magnetic sensor, an optical sensor, or the like is mounted as a rotor position detecting means. However, as long as a torque due to electromagnetic force is simply generated, the position detecting means is used. There is no need to provide it. However, by providing the position detection means, it is possible to grasp the state of rotation of the rotor (rotation angle, angular velocity, etc.), which is convenient for motor control. For example, taking a Hall element as an example, it is necessary to energize the element from an external power source. However, when a current is supplied by connecting a wire for energization to the element via the cap 30. In addition, since power is generated by the rotation of the ball screw nut 4 without using an external power source, the current generated by the induced electromotive force is supplied to the Hall element or stored in an external battery. The current may be supplied from the battery.

  In the present embodiment, the coil 8 is attached to the cylinder 23 side and the magnets 9 and 9 are attached to the ball screw nut 4 side. However, the coil 8 is attached to the ball screw nut 4 side and the magnets 9 and 9 are attached to the cylinder. It may be attached to the body 23 side, and a cylinder that is rotatably inserted into the cylinder 23 is provided, and a ball screw nut 4 is fitted into the cylinder, and a magnet or coil is provided on the outer periphery of the cylinder. May be attached, the other of the magnet or the coil may be attached to the inner periphery of the cylindrical body 23, and the coil and the magnet may be opposed to each other. In this case, when the cylinder is inserted into the cylinder 23, the cylinder can be supported by a plurality of ball bearings, so that a situation where the magnet or the coil shakes and the coil and the magnet come into contact with each other is prevented. Can do. Incidentally, although the motor 1 is a brushless motor in the present embodiment, various motors such as a DC motor, an AC motor, an induction motor, etc. can be used as long as they can be used as an electromagnetic force generation source.

  Further, the screw shaft 3 is rotatably engaged with the ball screw nut 4. Here, although the structure of the ball screw nut 4 is not particularly illustrated, for example, a spiral ball holding portion is provided on the inner periphery of the ball screw nut 4 so as to coincide with the spiral screw groove 3 a of the screw shaft 3. A large number of balls are arranged in the holding portion, and a passage is provided in the ball screw nut 4 to communicate both ends of the helical holding portion so that the balls can circulate. When the screw shaft 3 is screwed to the ball screw nut 4, the ball of the ball screw nut 4 is fitted into the helical screw groove 3a of the screw shaft 3, and the screw shaft 3 in FIG. Since the ball itself rotates due to the frictional force with the screw groove 3a of the screw shaft 3 along with the linear motion in the vertical direction, a smooth operation is possible as compared with a mechanism such as a rack and pinion.

 As described above, when the screw shaft 3 is rotatably engaged with the ball screw nut 4 along the screw groove 3a, and the screw shaft 3 moves linearly in the vertical direction in FIG. Since the screw nut 4 is restricted from moving in the vertical direction in FIG. 1 by the cylindrical body 23 and is only allowed to rotate, the ball screw nut 4 is forcibly driven to rotate. That is, the linear motion of the screw shaft 3 is converted into the rotational motion of the ball screw nut 4 by the above mechanism. Therefore, the ball screw nut 4 is rotated by the linear motion of the screw shaft 3 in the vertical direction, and the motor 1 generates a torque that resists the rotation of the ball screw nut 4 due to the induced electromotive force.

 Further, in the present embodiment, when this electromagnetic shock absorber is applied particularly to a vehicle, it is between the inner periphery of the bump rubber receiver 38 provided at the upper end in FIG. The provided seal member S, cylindrical body 23 and outer cylinder 20 prevent stepping stones from the road surface, rainwater, etc. from directly hitting the ball screw nut 4, the motor 1 and the screw shaft 3. Bearings 21, 22 are provided between the body 23 and the outer cylinder 20, thereby preventing the screw shaft 3 from being shaken with respect to the cylinder body 23 and the ball screw nut 4. It is possible to prevent a load from being concentrated on (not shown) and to avoid a situation where the ball or the screw groove 3a of the screw shaft 3 is damaged. In addition, since the ball or the screw groove 3a of the screw shaft 3 can be prevented from being damaged, the smoothness of each operation of the rotation of the screw shaft 3 and the ball screw nut 4 or the movement of the electromagnetic shock absorber in the expansion / contraction direction can be maintained. Since the smoothness of each of the above operations can be maintained, the function as an electromagnetic shock absorber is not impaired, and consequently failure of the electromagnetic shock absorber can be prevented.

  Further, by providing the bearings 21 and 22 between the outer cylinder 20 and the cylindrical body 23, the inner cylinder 23 is misaligned with respect to the outer cylinder 20, and the inner periphery of the upper end portion of the outer cylinder 20 is the cylindrical body 23. The situation which bites the outer periphery is prevented, and the deterioration of the sealing performance between the outer cylinder 20 and the cylinder body 23 is thereby prevented.

  In turn, in the electromagnetic shock absorber according to the present embodiment, a mount M is provided on a cap 30 provided on the upper portion of the cylindrical body 23 so that the mount can be mounted on a vehicle. At the same time, the bracket B provided at the lower end of the outer cylinder 20 is attached to the axle (not shown), so that the electromagnetic shock absorber is interposed between the vehicle body and the axle. The mount M includes a joint portion 36 on which the vibration isolating rubber 37 is sintered, an annular holding portion 34 that holds the annular anti vibration rubber 37, and an upper suspension that extends from the outer periphery of the holding portion 34. The lower suspension spring receiver 31 is provided on the outer periphery of the outer cylinder 20 and at the same time, the upper suspension spring receiver 32 on the mount M side and the lower suspension spring receiver 31 are illustrated. A suspension spring 33 is interposed therebetween. Further, a bump rubber 40 is provided on the inner peripheral side of the lower end in FIG. 1 of the holding portion 34, and the bump rubber 40 is formed into a cylindrical body by a step portion 34 a provided on the inner peripheral side of the lower end of the holding portion 34. An axial core is shown for 23. The bump rubber 40 and the bump rubber receiver 38 constitute a bump stopper.

  Therefore, by configuring as described above, the cylinder body 23 is attached to the vehicle body side, so that the motor 1 is arranged on a so-called spring. That is, when the electromagnetic shock absorber is applied particularly to a vehicle, it is possible to prevent a large load from being directly input to the motor 1 from the road surface by disposing the motor 1 on a spring and damage the motor 1. Opportunities can be reduced. Further, by arranging the motor 1 on the vehicle body side, it becomes easy to connect the electric wire 10 extending from the upper end side in FIG. 1 of the cap 30 to an external control device and control circuit. Therefore, the chance of damage to the electric wire 10 can be reduced.

  In the present embodiment, the upper suspension spring receiver 32 is provided on the mount M, the bump rubber 40 is provided on the mount M, and the bump rubber receiver 38 that receives the bump rubber 40 is provided on the outer cylinder 20. Since the shock load when the shock absorber fully bounces is transmitted to the vehicle body, it is possible to prevent the motor 1 from being damaged in this respect as well.

  Although the electromagnetic shock absorber is configured as described above, by adopting the above configuration, the motor 1 is formed in the cylindrical body 23, and the motor 1 is placed on the screw shaft 3 like the conventional electromagnetic shock absorber. Since it is not necessary to provide it vertically, the stroke required for the shock absorber can be secured and the basic length can be shortened. That is, it can be applied to a part where the installation space is limited, and a necessary stroke can be secured. That is, space saving can be achieved. Therefore, particularly when an electromagnetic shock absorber is applied to a vehicle, the basic length can be shortened, and the stroke of the shock absorber required for the vehicle can be secured, so that the mounting property to the vehicle is improved. In the present invention, the ball screw nut 4 is linearly moved in the vertical direction in FIG. 1 to rotate the screw shaft 3, and the rotational motion of the screw shaft 3 is transmitted to the motor 1. The basic length can be shortened, it is advantageous in terms of securing the stroke, and the mountability on the vehicle is also superior. This is because when the screw shaft 3 is rotated and the same power transmission means as that of the present invention is applied to the end of the screw shaft 3, the same stroke as that of the electromagnetic shock absorber of the present invention is ensured. The length obtained by adding the axial length of the ball screw nut 4 to the axial length of the power transmission means D (more precisely, the length from the lower end in FIG. 1 of the housing 9 to the upper end in FIG. 1 of the housing cap 13). This is because the basic length must be longer than that of the electromagnetic shock absorber of the present invention.

  Subsequently, the operation will be described. When the outer cylinder 20 expands and contracts to the electromagnetic shock absorber, that is, when the outer cylinder 20 moves in the vertical direction in FIG. 1, the screw shaft 3 connected to the outer cylinder 20 also performs a linear motion in the vertical direction. The linear motion of the screw shaft 3 is converted into a rotational motion of the ball screw nut 4 by the ball screw mechanism of the ball screw nut 4 and the screw shaft 3.

  When the ball screw nut 4 exhibits a rotational movement, the magnets 9 and 9 attached to the ball screw nut 4 rotate with respect to the coil 8 attached to the cylindrical body 23. Then, the coil 8 in the motor 1 crosses the magnetic field of the magnets 9 and 9, and an induced electromotive force is generated in the coil 8, and each electrode of the motor 1 is short-circuited as described above. Generates torque that resists the rotation of the ball screw nut 4 caused by the induced electromotive force, and the torque that resists the rotation of the ball screw nut 4 suppresses the rotational motion of the ball screw nut 4.

  The action of suppressing the rotational movement of the ball screw nut 4 works to suppress the linear movement of the screw shaft 3 in the vertical direction, so that it acts as a damping force that suppresses the linear movement of the screw shaft 3 and absorbs vibration energy. ease.

  As described above, the function as an electromagnetic shock absorber can be exhibited by a series of operations. In the present invention, since the motor 1 is formed in the cylindrical body 23, the basic length is shortened while ensuring the stroke of the electromagnetic shock absorber as described above. Since magnets and coils can be formed over substantially the entire length of the cylinder 23 that was a dead space, only the motor can be enlarged without increasing the size of the electromagnetic shock absorber. That is, since the motor output can be increased without increasing the size of the electromagnetic shock absorber, it is possible to generate a high damping force in the electromagnetic shock absorber.

  Furthermore, since the motor 1 is housed in the cylinder body 23 and the cylinder body 23 functions as a frame of the motor 1, the electromagnetic shock absorber can be formed slim and space-saving. Will improve.

  In addition, the motor 1 does not have to be attached to the electromagnetic shock absorber as an independent component, and the motor 1 and the electromagnetic shock absorber are integrated, so that it is more durable than conventional electromagnetic shock absorbers against impacts from the road surface or the like. Excellent.

  Furthermore, compared to the case where the motor is an independent part, parts such as a bracket, bolts and nuts for attaching the motor to the electromagnetic shock absorber main body are not required, so the number of parts can be reduced.

  Therefore, assembly and processing become easy, and productivity can be improved.

  Furthermore, the number of parts is reduced, the number of processing steps can be reduced, and the productivity is improved, so that the production cost can be kept low.

  Next, a second embodiment of the present invention will be described. As shown in FIG. 2, the electromagnetic shock absorber in the second embodiment is provided with a plurality of heat radiation fins F on the outer periphery of the cylindrical body 23 of the electromagnetic shock absorber in the first embodiment. It is omitted. Since other configurations are the same as those of the first embodiment, only the same reference numerals are given, and detailed description thereof is omitted.

  The fins F are thin-walled and are provided on the outer periphery of the cylinder 23 so as to face the coil 8 attached in the cylinder 23. Therefore, when the ball screw nut 4 rotates, an electric current flows through the coil 8 due to the induced electromotive force generated in the coil 8, and the coil 8 generates heat. Then, the temperature of the motor 1 itself rises, but this heat is transmitted to the cylindrical body 23 but is effectively dissipated by the fins F, so that the heat can be prevented from being accumulated in the cylindrical body 23. . Here, the cylindrical body 23 is sufficiently longer than the motor, and particularly when the electromagnetic shock absorber is applied to a vehicle, the electromagnetic shock absorber is attached between the axle and the vehicle body. Wind hits the fins F of the cylindrical body 23 and can effectively dissipate heat.

  Then, since the temperature rise of the motor 1 can be suppressed, insulation due to adverse effects that exceed the temperature rating of the motor 1, for example, chemical change of the insulating film of the conductive wire forming the coil 8 of the motor 1 due to heat generated by the motor 1 itself, etc. As a result, it is possible to prevent a situation in which the motor 1 itself is damaged due to leakage of electric current.

  Further, since the motor 1 does not have an individual frame, the heat generated by the motor can be prevented from being trapped in the motor.

  In the illustrated case, a plurality of fins F are provided on the outer periphery of the cylindrical body 23. However, in addition to the fins F, it is only necessary to increase the surface area of the cylindrical body 23 so as to improve heat dissipation. Concavities and convexities may be formed, or other shapes may be employed.

  Further, even in the electromagnetic shock absorber according to the second embodiment, it is needless to say that a damping force can be generated as in the case of the electromagnetic shock absorber according to the first embodiment, and further, the basic length of the electromagnetic shock absorber. Since the stroke can be shortened and the stroke can be secured, the same effect as that of the first embodiment can be achieved.

  In the above description, the case where the electromagnetic shock absorber is applied particularly to a vehicle has been described. However, it goes without saying that the electromagnetic shock absorber can be used in a portion where the normal shock absorber is used.

  This is the end of the description of the embodiment of the present invention, but the scope of the present invention is of course not limited to the details shown or described.

It is a longitudinal cross-sectional view of the electromagnetic shock absorber in the 1st Embodiment of this invention. It is a longitudinal cross-sectional view of the electromagnetic shock absorber in the 2nd Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Motor 3 Screw shaft 3a Screw groove 4 Ball screw nut which is a screw nut 7 Core 8 Coil 9 Magnet 20 Outer cylinder 21, 22 Bearing 23 Cylindrical body which is a support member 31 Lower suspension spring receiver 32 Upper suspension spring receiver 33 Suspension spring 38 Bump rubber 40 Bump rubber B Bracket C Car body F Fin M Mount

Claims (7)

An electromagnetic shock absorber comprising: a screw shaft that is rotatably screwed into a screw nut that is rotatably connected to a support member; and a motor, and a motor that suppresses relative movement in the axial direction between the screw nut and the screw shaft. Is composed of one of a magnet or a coil connected to the screw nut and the other of the magnet or the coil fixed to the support member, and generates an electromagnetic force in the motor, and this electromagnetic force suppresses the rotation of the screw nut. Thus, the electromagnetic shock absorber is used as a damping force for suppressing the linear motion of the screw shaft in the axial direction. The support member is a cylinder, and the screw nut is rotatably fitted in the cylinder, and one of the magnet or the coil connected to the screw nut is opposed to the other of the magnet or the coil provided on the periphery of the cylinder. The electromagnetic shock absorber according to claim 1. The electromagnetic shock absorber according to claim 2, wherein the outer peripheral shape of the cylindrical body is a shape having an increased outer peripheral surface area. The electromagnetic shock absorber according to claim 3, wherein irregularities or fins are formed on the outer periphery of the cylindrical body. The electromagnetic shock absorber according to claim 2, wherein an outer cylinder connected to one end of the screw shaft and covering the screw shaft is provided, and a bearing is provided between the outer tube and the cylindrical body. The cylinder is connected to the vehicle body side of the vehicle, the outer cylinder is connected to the axle of the vehicle, a suspension spring receiver is provided on the outer periphery of the cylinder and the outer cylinder, and a suspension spring is interposed between the suspension spring receivers. The electromagnetic shock absorber according to claim 5. 7. A mount for attaching the cylinder to the vehicle body of the vehicle is provided at the end of the cylinder, an upper suspension spring receiver and a bump rubber are provided on the mount, and a bump rubber receiver is provided on the outer cylinder side. The electromagnetic shock absorber described in 1.

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